Feel free to move this thread around to a more fitting spot as it develops, but I think this is the proper place for now.Post interesting science/math/astronomy videos here!

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." - Douglas Adams

Neat! On the old forum I also talked about the idea of surrounding a region of space with a sufficiently massive shell such that it forms a black hole and dooms the interior, even as the interior doesn't notice anything weird whatsoever until it gets swept up in a singularity. The challenge question posed about trying to escape this scenario is interesting!

Added: And yes, one of the two plans will definitely NOT work, while the other potentially could work, and by common intuition that is not necessarily obvious. But the fun part, which I won't spoil, is showing why one plan is better, using the Penrose diagram. If you understand how the Penrose diagram works from his presentation, then this is actually not too hard to demonstrate, and the physical interpretation of it is very cool. If anyone is trying this challenge and is stuck or confused about some aspect of it, feel free to ask questions.

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." - Douglas Adams

I thought he said watsisname too Unless you really said that, I think he said "whatshisname"

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." - Douglas Adams

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." - Douglas Adams

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." - Douglas Adams

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." - Douglas Adams

Happy to see 12017 catching on, and hopefully the year we get our first direct image of a black hole event horizon.

Challenge answer is really cool. It's so weird to think that the 'Disco Ball' does indeed reflect the light outward, but that outward is still towards the singularity, sweeping up the Earth with it. Perhaps the most intuitive explanation is with the 'flow of space' analogy for space-time curvature. Once the shell of light has come within its own Schwarzschild radius, it is causing the space immediately behind it to flow inwards greater than the speed of light. It's as if the light is digging a hole for itself, and the hole is so steep that it can't climb back out. So even if you can perfectly reflect the light, you can't reflect this inward rush of curved space-time. It sweeps up everything inside the event horizon, including the reflected light pulse, and consumes the Earth in singularity.

...which, I think, is the coolest description of this Kugelblitz weapon ever. The target is destroyed by space itself!